Video display system

ABSTRACT

Teletype information signals from two different stock exchanges are stored in respective recirculating registers. Under the control of timing signals, the contents of the two registers are periodically advanced and alternately supplied to a character generator which converts the coded teletype information into an electronic array of corresponding letters or figures. Each array is sequentially scanned by a controlled electrical commutator and the scanned signals are supplied to a cathode ray tube for reproduction. The horizontal and vertical scanning coils for the tube are rotated 90* from their usual positions such that information signals are displayed as advancing transversely across the face of the device.

United States Patent Goldman et al. [4 1 July 11, 1972 541 VIDEO DISPLAY SYSTEM 3,423,749 1/1969 Newcomb ..340/324 A 3,404,309 /1968 Masselletal. ....340/324A [72] lnvenm's' David Gddman 3,406,387 10/1968 Wenne ..340/324A Henry N. Oppenheimer, Larchmont, both of NY.

Primary Examinerl(athleen H. Claffy [73] Assignee: Columbia Broadcasting System, Inc., New Assistant Examiner-Thomas L. Kundert York, Artorney-Brumbaugh, Graves, Donohue & Raymond 22 Filed: Feb. 11 1971 1 [57] ABSTRACT 21 A 1. No.: 114 669 1 pp Teletype infonnation slgnals from two d1fferent stock Related U.S. A li ti D t exchanges are stored in respective recirculating registers. f Under the control of timing signals, the contents of the two re- [63] dcontgmanon 0 734982 June 1968 aban' gisters are periodically advanced and alternately supplied to a one character generator which converts the coded teletype information into an electronic array of corresponding letters or 331232 figures. Each array is sequentially scanned by a controlled 58 d A 152 154 electrical commutator and the scanned signals are supplied to I 1 o are a cathode ray tube for reproduction. The horizontal and vertical seaming coils for the tube are rotated 90 from their usual [56] References Cited positions such that information signals are displayed as ad- UNITED STATES PATENTS vancing transversely across the face of the device.

3,422,420 1/1969 Clark ..340/324 A 5 Claims, 8 Drawing Figures GATE l5 c a l2 GROUPS I cu" l 6 Serial or 5-511 21- on Parallel 52 C'MRACTER Parallel TeIelyPB Trcnster nigrs igRs 34 BUFFER Trunsler RECIBTJCFEE'STING GATE I Trunsler 8B:

'0 14 R Inhibit Character 5,22%? :snm "M Available CONTROL I66 1 22 GENERAAGTIER I Line I I6"! SHIFT SI GN A L T120 GENERATOR 50 224 15 Level I I [94 I RATE AND 15 Lev" I CHARACTER OFFSET THREE STAGE 26 TRANSFER ADVANCE coumea BINARY CHARACTER QQES O L c h I CONTROL PROGRAMMER E eoumsa Riggs OHIC 8' Present 75 "H 228 "79 I6 20 I2 1 W I68 Hi Is 0-5 Ttll'YP 11mm g: E 56 BUFFER Transler flzcgi l arms fills-J a u lnhibil |02- gagg' g ?J- I76 new Chu!:1rter CO OL I78 SHIFT Av i bl 1- 24 cliliifinl u a l L 5 I SIGNAL Sloll- GENERATOR Leve mass 2% was: 2G523E mg, az/sari Charon" CONTROL PROGRAMMER 17 COUNTER CONTROL P 1 12a resen Patented July 11, 1972 6 Sheets-Sheet 4 Patented July H, 1972 6 Sheets-Sheet 6 COLUMN A B C D E A B C D E A B C D E A BC D E A B C DE AB ,;ooooooooooooooooo OOOOOOOOOOOOOOOO 000 o o o o 0 yo 0 o O Y o o o o o o o o o o 0 o o o o o o o o o o o o o o o o o o o o o mumwmmmnmmw 2| OOOOO ooooooooo Q o o o o o o o o FIG. 4

6 o o o o o o o o o o o o o o o o o o o VIDEO DISPLAY SYSTEM This application is a continuation of application Ser. No. 734,082 filed June 3, 1968 and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to television display systems and, more particularly, to television display systems which provide a visual display of characters represented by telegraph and the like signals.

There have been developed recently display systems for displaying telegraph information signals on a screen. Such systems implement the visual reproduction of the telegraph signals on a screen by stroke writing techniques, by scanning perforated paper tape with a television camera and by employing high speed electronic video switching systems. Among the many services utilizing such systems is the stock market quotation service. Because of the ever increasing sales transactions occurring in the major stock exchanges, the number of brokerage offices having communications links with the exchanges has correspondingly increased. A great many of the larger offices already have display systems including screens for displaying an up-to-the-minute visual indication of stock quotation prices. However, many of the smaller offices do not have such screens or like display devices because of the complexity and high cost of the systems associated with the screens.

SUMMARY OF THE INVENTION device.

These and other objects of the present invention are accomplished by the video display generator of the present invention. In the generator, character representative telegraph signals are stored in a recirculating buffer, readout and simultaneously restored in the buffer under the control of timing signals. The readout character representative signals are then supplied to a character generator which converts the information signals into an array of electrical elements forming the characters represented by the telegraph information signals. This array is scanned to thereby provide character representative signals and the character representative signals are thereupon supplied to an image reproducing device for reproduction.

In a preferred embodiment of the invention, the deflection means of the image reproducing device are angularly rotated such that line scanning takes place in a substantially vertical direction, field scanning takes place in a substantially horizontal direction and the information is reproduced as precessing across the face of the image reproducing device. Also, offset counting devices are provided to produce an incremental positioning of the reproduced information on the face of the image reproducing device in each successive field or frame to create the effect of motion by the reproduced information following a transfer of character representative telegraph signals to the recirculating buffer. In addition, the generator is provided with a pair of channels for receiving character representative telegraph signals from two different sources and the characters represented by the signals are displayed on opposite halves of the face of the image reproducing device.

BRIEF DESCRIPTION OF THE DRAWING In the Drawings:

FIGS. 1A and 1B are a schematic block diagram of an illustrative video display generator arranged according to the present invention;

FIGS. 2A, 2B and 2C are schematic block diagrams of certain of the elements in the video display generator of FIG. I;

FIG. 3 is a block diagram illustrating the alignment between FIGS. 1A and 1B and between FIGS. 2A, 2B and 2C;

FIG. 4 is a pictorial representation of the selective magnetization of the magnetic cores of the core matrix of the character matrix generator of the FIG. 1 video display generator; and

FIG. 5 is a pictorial representation of the telegraph information as it is displayed by the image reproducing device of the FIG. 1 video display generator.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the illustrative embodiment of a video display generator arranged according to the present invention, as shown in FIGS. IA and IB, telegraph information signals from two different sources, such as, for example, the New York and American Stock Exchanges, respectively, are supplied via teletype lines (not shown) to a pair of level converters I0 and I2, respectively.

The telegraph information signals are supplied as pulsating d-c signals and each character of information comprises six bits, bit 0 determinative of whether the character is a letter or a figure and bits 1-5 determinative of the particular letter or figure. In the level converters 10 and 12, the pulsating d-c telegraph signals are converted into pulsating logic level signals. In particular, the level converters reduce the peak amplitudes of the signals from approximately volts to approximately 10 or 12 volts. From the level converters l0 and 12 the reduced amplitude telegraph signals are transferred serially to a pair of shift registers 14 and 16, respectively. Each register comprises 12 groups of six-bit shift registers serially interconnected and, hence, each register is capable of storing 12 characters. The output terminals of the six devices, which may be, for example, conventional flip-flop circuits, comprising the last group in each of the registers 14 and 16 are connected to a pair of gate circuits I8 and 20, respectively. The gate circuits I8 and 20 may be conventional and, hence, for purposes herein, each circuit comprises 6 and gates, each and" gate having one input terminal coupled to an individual flip-flop in the last group register in the registers 14 and 16, respectively.

The 12 groups of shift registers in the registers 14 and 16 are further coupled to a pair of voltage generators 22 and 24, respectively, which may be, for example, conventional adding circuits, and hence, which develop voltage signals, the amplitudes of which correspond to the number of groups in the registers 14 and 16 containing telegraph information. For example, where all 12 groups contain characters, the generators 22 and 24 may produce voltage signals having amplitudes of 24 volts, respectively. Where six of the 12 groups contain information, the amplitudes of the generated signals may be 12 volts. From the voltage generators 22 and 24 the voltage signals are supplied to a pair of rate and transfer control circuits 26 and 28, respectively. Depending upon the amplitudes of the voltage signals developed by the generators 22 and 24 the control circuits 26 and 28, which may comprise amplifier circuits preceded by voltage detection networks, develop either so-called 15 level" signals or 7.5 level signals and supply these signals to a pair of character advance control circuits 30 and 32 via a pair of conductors 75 and 74, respectively.

Specifically, when eight or more groups in the registers 14 and 16 contain information the generators 22 and 24 develop signals having amplitudes above, for example, 16 volts, which drive the control circuits 26 and 28 and cause a 15 level signal to be produced. When less than eight but at least one group in each of the registers contains information, the generators 22 and 24 develop signals having amplitudes below, for example, l6 volts, which drive the control circuits 26 and 28 and cause a 7.5 level signal to be produced. As will be explained hereinafter, the 15 level signal and the 7.5 level signal correspond to character progression speeds and control the horizontal positioning of the telegraph information as it is displayed by the image reproducing device of the present invent A t A .1 hr

tion. Moreover, when a l5 level signal is developed, the transfer of information out of the registers 14 and 16 takes place at a rate which doubles the rate of transfer when the 7.5 level signal is present, as will also be apparent hereinbelow.

In response to character present or CPFF signals generated by the character advance control circuits 30 and 32, the control circuits 26 and 28 emit gating signals and supply these gating signals to the other input terminals of the six and gates forming each of the gate circuits l8 and 20, respectively. The character present signals are generated when the generator components following the shift registers 14 and 16 are available to accept another character, as will be explained in detail hereinafter. When enabled by the gating signals generated by the circuits 26 and 28, the gate circuits transmit, in parallel, the bits stored in the last group registers of the registers 14 and 16 to a pair of six-bit buffers 34 and 36.

The six-bit buffers 34 and 36, which may be of conventional construction, supply voltage level signals corresponding to the character bits transferred to the buffers by the gates 18 and 20, respectively, to a pair of 32 character recirculating buffers 38 and 40. In addition, the buffers 34 and 36 supply a pair of character available signals to the character advance control circuits 30 and 32. This initiates a sequence of operation which enables the 32 character recirculating buffers 38 and 40 to accept the new six-bit characters stored in the buffers 34 and 36, respectively. As will be explained hereinafter, 32 characters are stored in each of the buffers 38 and 40 and continuously recirculated and read out under control of certain timing signals. When a new character is supplied to either buffer, the character is stored and then readout, the oldest character in the buffer being dropped.

To understand the operation of the 32 character recirculating buffers 38 and 40, as well as the character advance control circuits 30 and 32, it is necessary now to explain the timing signal control circuitry of the video signal generator. As shown in H0. 18, the generator comprises a phase locked 2 megaHertz per second (mH/s) clock 42 which emits pulses having a pulse width of one-half a microsecond. The clock 42, which may be, for example, a conventional crystal oscillator, generates phase locked k microsecond pulses and supplies these pulses to a l28 bit binary counter 44 through a conductor 45. The counter 44 may be of conventional construction and, hence, includes seven bistable devices A, B, C, D, E, V, u to accumulate a count of 128. The count is reached in 64 microseconds. The number 128 constitutes the number of bits which will be present in any given scanning line displayed by the image reproducing device of the video display generator, as will be more apparent hereinbelow.

Connected to the l28 bit binary counter 44 is an eight line binary counter 46 comprising three bistable devices. The counter 46 is advanced one position each time the counter 44 reaches a count of 128 or every 64 microseconds. As will also be explained hereinafter, eight scanning lines of the video display are allotted to each character of telegraph information, five lines comprising the information and three lines comprising spaces. A 32 group counter 48 comprising five bistable devices is coupled to the counter 46 and is stepped each time the counter 46 reaches a count of 8. This counter counts the number of characters displayed by the image reproducing device and continues to count until 32 characters are displayed during each field scansion, the same number of characters which are stored and recirculated in the buffers 38 and 40. As thus far described, there is provided a counting arrangement for 256 lines, each line comprising a maximum of I28 bits of information.

Because there are 262% lines in each television field scansion, the counters 44, 46 and 48 are not reset upon a count of 256 lines. Coupled to the 32 group counter is a bistable device 50 which is set into the l state when the counter 48 reaches a count of 256. The l side of the device 50 is coupled to the input terminals 52a and 54a of a two input and gate 52 and a three input and" gate 54, respectively. The other input terminal 52b ofthe gate 52 and another input terminal 54b of the gate 54 are coupled together and through a conductor 55 to a timing signal decode network 56. The network 56, which may comprise suitable gating circuits and amplifiers for decoding the counts accumulated in both the 128 bit counter 44 and the eight line counter 46, generates a logic level signal each time a count of 6 is accumulated by the counter 46. With the simultaneous presence of the line 6 signal and the l signal from the device 50, the gate 52 is enabled and generates a reset level signal. The third input terminal 54c of the gate 54 is coupled via a conductor 57 to the network 56 which generates a pulse each time a count of 64 is accumulated in the counter 44. This pulse enables the gate 54 for a period of 0.5 microseconds and the gate emits a 0.5 microsecond reset pulse.

At the end of a count of 262% lines, therefore, the reset pulse is generated. This pulse resets the bistable device 50 and the counters 44, 46 and 48. The reset pulse is also supplied to a vertical sync and horizontal sync generator 58 which generates a vertical sync signal. Upon resetting of the bistable device 50 the gate 52 is disabled. Accordingly, the reset level signal is generated at a count of 262 lines and is terminated at a count of 262% lines.

In the vertical sync and horizontal sync generator 58, the reset pulses are shaped and amplified and supplied as vertical sync pulses through a conductor 59 and a branch conductor 59a to a conventional video driver 60 and a scanning wave generator 62. The generator 58 is also coupled to the timing signal decode network 56 through a conductor 63 and receives a T128 pulse from the network 56 each time a count of 128 is accumulated in the counter 44 or every 64 microseconds. In the generator 58, the T128 pulse is shaped and amplified and thereupon supplied as a horizontal sync pulse through a conductor 64 and its branch conductor 64a to the video driver 60 and the scanning wave generator 62, respectively.

As thus far described, the timing signal decode network 56 is responsive to the states of the bistable devices of the counters 44 and 46 for developing a T64 signal, a T128 signal and a line 6 signal, respectively. The network 56 also generates 23 timing signals TO-T22 a total number of four times during each counting cycle by the counter 44. In other words, the network 56 decodes the states of the first five bistable devices to generate the signals TO-T22 once every 16 microseconds, that is, from counts 0-31, 32-63, 64-95 and 96-127. The decode network also generates a T pulse having a pulse width of one-half microsecond, each time the counter 44 reaches a count of 120.

The last two bistable devices in the 128 bit counter 44, i.e., the 32nd bit and the 64th bit bistable devices, are labeled v and u, respectively. As will be explained in more detail hereinbelow, the state of the u bistable device controls the vertical display of information on the face of the image reproducing device. Specifically, when the u bistable device is set to the l" state (T64T127), information is displayed in the lower half of the image reproducing device. When the device is in the "0 state (TO-T63), information is displayed on the upper half of the image reproducing device. The state of the v bistable device also controls the vertical display of information on the face of the image reproducing device. In particular, when the v bistable device is in the 0" state (TO-T31, T64-T95), information is displayed on the upper half of either the upper half or the lower half of the image reproducing device and when the device is in the l state (T32-T63, T96-T127), information is displayed on the lower half of either the upper half or the lower half of the image reproducing device.

As above-mentioned with reference to FIG. 1A, when the character bits are transferred from the gates 18 and 20 to the six-bit buffers 34 and 36, respectively, the buffers supply a pair of character available signals to the character advance control circuits 30 and 32. Referring to FIGS. 2A, 2B and 2C, there is shown in detail certain of the components of the video display generator of the present invention. Because the upper channel and lower channel have identical components, only the components of the upper channel, referred to hereinafter as the New York Stock Exchange channel, are shown in detail. The corresponding components of the lower channel, hereinafter referred to as the American Stock Exchange channel, are shown generally.

As shown in FIG. 2B, the character advance control circuit 30 comprises a first and gate 66. One input terminal 66a is supplied with the reset level signal developed by the gate 52 (FIG. 1B) and the other input terminal 66b is coupled to the six-bit buffer 34 (FIG. 1A) and receives a character available signal when the buffer 34 is loaded. The simultaneous presence of the character available signal and the reset level signal enables the gate and the gate supplies a pulse to the set input terminal 68a of a character present flip-flop 68.

When set to the l state, the character present flip-flop 68 supplies a character present (CPFF) signal from its set output terminal 68b through a conductor 69 to the input terminals 70a and 72a of a pair of three input and gates 70 and 72, respectively. The output terminal of the character present flipflop 68 is also coupled to the rate and transfer control circuit 26 (FIG. 1A) via a conductor 73 such that when a character present signal is available, the circuit 26 is disabled. The reset level signal is coupled from the input terminal 66a of the gate 66 to the second input terminals 70b and 72b of the gates 70 and 72. The other input terminals 700 and 72c of the and gates 70 and 72, respectively, are coupled via the conductors 74 and 75, respectively, to the rate and transfer control circuit 26 (FIG. 1A) which supplies either a 7.5 level signal or a level signal to the gates 70 and 72, respectively. As abovementioned, a 7.5 level signal is generated when less than eight but at least one group of registers in the register 14 contains information and a 15 level signal is generated when eight or more groups of registers in the register 14 contain information. Depending upon whether the 7.5 level signal or the 15 level signal is supplied from the rate and transfer control circuit 26, either the gate 70 or the gate 72 will be enabled.

The output terminal 70d of the and gate 70 is coupled to the input terminal 78a of the flip-flop circuit 78 which is alternately set and reset each time the and gate 70 is enabled by the simultaneous presence of the reset level signal, the CPFF signal and the 7.5 level signal. The output terminal 72d of the and" gate 72 and the set output side 78b of the flipflop 78 are coupled together and to the shift input terminal 80a of a two stage binary counter 80. It can be seen that twice as many shift pulses will be supplied from the and" gate 72 to the input terminal 80a of the binary counter 80 as will be supplied from the flip-flop circuit 78. This is true because the flipflop circuit 78 will be alternately enabled and disabled in response to the simultaneous application of the reset level signal, the CPFF signal and the 7.5 level signal to the input ter minals of the gate 70 whereas the enabling of the gate 72 will correspondingly implement the generation of a shift pulse to the binary counter 80. Hence, counting by the counter 80 when a 15 level signal is present will occur twice as fast as counting when a 7.5 level signal is present.

The application of a shift pulse from either the and" gate 72 or the flip-flop circuit 78 to the input terminal 80a of the two stage binary counter 80 initially resets the counter to the 0 state. The two bistable devices comprising the binary counter 80 are coupled to a decoding network comprising a count 0 and gate 82, a count 1 and" gate 84, a count 2 and gate 86 and a count 3 and gate 88. As is understood in the art, the count 0 and gate 82 is enabled each time both stages of the counter 80 are in the 0 states; the and gate 84 is enabled each time the counter 80 has counted to l; the count 2 and gate 86 is enabled each time the counter 80 has accumulated a count of 2; and the count 3 and gate 88 is enabled each time the counter has accumulated a count of 3.

The output terminal of the count 0 and gate 82 is connected through a conductor 90 and its branch conductor 90a to one input terminal 92a of an and" gate 92 located in an offset counter programmer 94 and to one input terminal 96a of an and gate 96 located in a recirculating buffer control circuit 98 (FIG. 2A). The American Stock Exchange channel similarly includes an offset counter programmer 100' and a recirculating buffer control circuit 102. The recirculating buffer control circuits 98 and 102 control the storage and shifting of telegraph characters in the 32 character recirculating buffers 38 and 40, respectively, as will be explained hereinbelow.

The output terminal ofthe count" 1 and" gate 84 (FIG. 2B) is connected to one input terminal 1040 of a second and" gate 104 located in the offset counter programmer 94. The output terminal of the count 2 and gate 86 is also connected to one input terminal 106a ofan and" gate 106 located in the offset counter programmer 94 while the output terminal of the count 3 and" gate 88 is connected to the reset input terminal 680 of the character present flip-flop 68. A conductor 108 couples the input terminals 92b, 104b and 106b of the and" gates 92, 104 and 106 together and supplies these terminals with the reset level signal. The input terminals 920, 1041: and l06c of the gates are connected together via a conductor 110 and to the set output terminal 68a of the character present flipflop 68. It can be seen that the and gates 92, 104 and 106 will be sequentially enabled as the counter 82 counts from 0 to 3 when a reset level signal is generated at the end of a count of 262 lines and as long as the character present flipflop 68 is set.

A pair of branch conductors 108a and 110a of the conductors 108 and 110, respectively, conduct the reset level signal and the CPFF signal to the input terminals 96b and 96c of the and" gate 96 in the recirculating buffer control circuit 98 and to the input terminals l12b and 112a of an and gate 112 in the buffer control circuit 98 (FIG. 2A). A conductor 111 couples the 0 side of the flip-flop 78 to the fourth input terminal 96d of the and gate 96. Only when the flip-flop 78 is set into the 1 state, does the output signal FF78 from the 0 side of the flip-flop 78 tend to enable the gate 96.

When the reset level signal and the CPFF signal are simultaneously present, the and gate 112 is enabled and drives an amplifier 114 into conduction, The output terminal 114b of the amplifier 114 is coupled to the output terminal 116b of an amplifier 116 and to one input terminal 118a of an and gate 118. The other input terminal 118b of the and gate 118 is coupled via a conductor 120 and its branch conductors 120a, 12% and 1200 to the output terminal of the and" gate 96, the input terminal of a common emitter amplifier 122 and to the input terminals of six and gates 124, 125, 126, 127, 128 and 129 located in the 32 character recirculating buffer 38. For the sake of simplicity, only gates 124 and 129 are shown.

When the count 0 signal, the reset level signal, the CPFF signal and the FF78 signal are supplied to its input terminals 96a, 96b and 96c and 96d the gate 96 is enabled and supplies an inhibit signal to the input terminal 118!) of the and gate 118 to thereby disable the gate, to the input terminal of the common emitter amplifier 122 and to the input terminals of the gates 124-129 to disable-these gates. The common emitter amplifier 122 inverts the inhibit signal to provide an inhibit signal and this signal is supplied to the input terminals of six and" gates 130, 131, 132, 133, 134 and 135 also located in the recirculating buffer 38. Hence, when the inhibit pulse is generated, only the gates 130-135 are enabled. These gates are enabled for a period of 32 microseconds, that is from the time it takes the counter 44 (FIG. 18) to count to 64 or from a count of 262 lines to a count of 262% lines.

The and" gates 124-129 are associated with the information already stored in the buffer 38 while the and gates 130-135 are associated with the new character bits supplied in parallel from the six-bit buffer 34 (FIG. 1A). In particular, the other input terminals of the and" gates 124-129 are coupled to the first stages in six shift registers 136, 137, 138, and 141, respectively, each shift register comprising 32 flip-flops. The and gates 130-135 are associated with the new character bits and their other input terminals are coupled in parallel to the six output terminals of the six-bit buffer 34 (FIG. 1A). The output terminals of the and gates 124-129 and 130-135 are coupled respectively to the input terminals of six or gates 142-147 which selectively transmit the bits supplied from either the and gates 124-129 or the "and gates 130-135. The bits transmitted by the or" gates 142-147 are thereafter supplied to the enabling input terminals of six flip-flop circuits 148-153, respectively. The set output terminals of the flip-flop circuits 148-153 are connected to the enabling input terminals of the last stages in the registers 136-141, respectively, and to the input terminals 154a, 155a, 156a; 157a, 158a and 159a of a six and" gate circuits 154-159, respectively, which make up a gate circuit 160.

The output terminal 1186 of the and gate 118 is coupled through a conductor 161 to the shift input terminals of the 32 flip-flops making up each of the shift registers 136-141. Initially, the and gate 118 is disabled by the application of the inhibit pulse to its input terminal 118b, notwithstanding the application of the amplified pulse to its other input terminal 1180. However, the output terminals 114k and 1160 of the amplifiers 114 and 116 are coupled together and through a conductor 162 to the shift input terminals of the flip-flop circuits 148-153. Accordingly, with the simultaneous presence of a reset level signal and a CPFF signal, the gates 130-135 of the buffer will be enabled by the inhibit pulse and a shift pulse is generated by the amplifier 114. The gates 130-135 will therefore pass the new character bits and these bits will be loaded into the flip-flop circuits 148-153 and read out. At the end of 262 lines, the reset level is removed from the input terminals of both gates 96 and 112 and these gates will be disabled. With the disabling of the gate 96, the inhibit signal is removed, the and gate 118 is enabled and the and" gates 124-129 are enabled. By reason of the phase inversion performed by the common emitter 122, the and gates 130-135 are disabled.

To implement the further shifting of information within the recirculating buffer 38 and the reading out ofinformation, the recirculating buffer control unit is provided with another and gate 164 having one input terminal 164a connected to a shift signal generator 166 (FIGS. 1A and 28) through a conductor 167 and its other input terminal 164b supplied with the 0.5 microsecond pulse T120 generated by the timing signal decode network 56 (FIG. 1B). The shift signal generator supplies a line 6 pulse to the recirculating buffer control circuit 98 such that after a scan period of six lines and 60 microseconds (T120), the and gate 164 is enabled and transmits the T120 pulse to the input terminal 116a of the amplifier 116. The amplifier 116 supplies a shift output pulse each time the and" gate 164 is enabled and supplies this pulse to the input terminal 118a of the and gate 118 and to the shift input terminals of the flip-flop circuits 148-153 through the conductor 162. Because the total number of scanned lines equals 262%, a total of 32 shift pulses will be supplied from the amplifier 116.

With the application of the amplified pulse to the input terminal 118a of the and" gate 118,21 shift pulse is supplied via the conductor 161 to the shift input terminals of the flip-flop circuits composing the registers 136-141. With the simultaneous generation of the two shift pulses and the enabling of the and gates 124-129, the bits stored in the first stages of the registers 136-141 are transmitted by the gates 124-129, loaded into the flip-flops 148-153, respectively, and supplied to the and gates 154-159, respectively. The newest bits defining a character are simultaneously shifted into the last stages of the registers 136-141 from the flip-flops 148-153, respectively. During the generation of the next 31 shift pulses, the bits in the registers 136-141 are shifted into the flip-flops 148-153, respectively, in the above described manner. At the end of 32 shift pulses, the newest information bits are stored in the first stages of the registers 136-141 while the oldest information bits are stored in the flip-flops 148-153. In this manner, when new information is again transmitted by the gates 130-135, the oldest information bits are dropped as the new information bits are loaded into the flip-flops 148-153.

The oldest bits are dropped because the registers 136-141 are inhibited from shifting, as above described.

The lower American Stock Exchange channel similarly contains a gate 168 comprising six and" gates 169, 170, 171, 172, 173 and 174 having input terminals 169a-174a coupled to the output flip-flop circuits in the 32 character recirculating buffer 40 and a shift signal generator 176 which supplies a line 6 pulse via a conductor 178 to the recirculating buffer control circuit 102. The other input terminals 154b-159b of the gates 154-159, respectively, are coupled together and, via a conductor 179, to the input terminals 180a, 182a, 184a, 186a and 1880 of five and gates 180, 182, 184, 186 and 188 in a character position control circuit 190 (FIG. 2B) and to the 0 side of the u bistable device in the 128 bit counter 44 (FIG. 1B). Appropriate current drivers may be inserted between the u bistable device and the gates, as is understood in the art. When the u bistable device is in the 0" state (TO-T63), the gates 154-159 are enabled and transmit the in formation bits. The other input terminals 169b-174b of the gates 169-174 respectively are also coupled together and, via a conductor 192, to the input terminals of five and gates composing a character position control circuit 193 (FIG. 2B) and to the 1" side of the u bistable device (FIG. 1B). These gates are enabled when the u bistable device is in the 1" state (T64-T127). As will be explained hereinafter, the bits transmitted by the gates 154-159 are displayed on the upper halfof the image reproducing device and the bits transmitted by the gates 169-174 are displayed on the bottom half of the image reproducing device.

The output terminals of the gates 154 and 169; and 170; 159 and 174 are tied together and coupled to the input terminals of a character matrix generator 194 (FIG. 2C). The character matrix generator 194 comprises a pair of decode networks 196 and 198 which comprise conventional gating circuitry for decoding the transmitted New York and American Stock Exchange information bits. The networks 196 and 198 are provided to decode the bits 1-5 from each gate circuit and 168 into a pair of pulses out ofa possible 64 pulses. Each network is provided with 32 output terminals 196a-196n and 198a-198n and these output terminals are coupled to the input terminals of 32 and gates 20011-200n and 202a-202n. The other input terminals of the gates 200a-200n and 202a-202n are coupled together and are supplied with the bit 0 pulse which, as above-mentioned, determines whether the coded information is a letter or a figure. The gates 200a-200n are enabled when bit 0 is a l" or a mark and the and" gates 202a-202n are enabled when bit 0 is a 0 or a space. Hence, if bits 0-5 correspond to a letter, only one of the and gates 200a-200n is enabled. If bits 0-5 correspond to a figure, only one of the and" gates 202a-202n is enabled.

The output terminals of the gates 200a-200n and 202a-202 n are connected to the input terminals of a pair of current driver matrices 204 and 206, respectively. The current driver matrix 204 comprises five columns and eight rows of current drivers and the current drivers are selectively coupled to the and" gates 200a-200n. For example, if the columns are labeled A, B, C, D, and E and the rows are labeled 1-8, a pulse corresponding to the letter A applied to an input terminal from one of the gates 200a-200n would energize the following current drivers: A2, A3, A4, A5, E2, E3, E4, E5, B1, C1, D1, and B4, C4, D4. In other words, the current drivers of the matrix are energized in a pattern which corresponds to the letter being transmitted. This will become more apparent hereinafter.

The current driver matrix 206 comprises five columns and 15 rows of current drivers and these current drivers are also selectively coupled to the and gates 202a-202n. For example, if the columns are labeled A, B, C, D and E and the rows are labeled 1-15, a pulse corresponding to the figure 4 applied from one of the gates 202a-202n would energize the following current drivers: A7, B6, B7, C5, C7, D4, D5, D6, D7, D8, D9, D10 and E7. Again, the array of current drivers being energized corresponds to the figure decoded by the decode network 198, as will be apparent hereinafter.

The 40 current drivers in the matrix 204 and the 75 current drivers in the matrix 206 are coupled via the output terminals -39 and 0-74, respectively, to the set input windings of corresponding magnetic cores of a core matrix 208. The cores of the matrix are arranged in a matrix of five columns labeled A, B, C, D and E and 23 rows labeled 1-23. As shown, the current drivers of the matrix 204 are respectively coupled to the set input windings of the magnetic cores occupying the first eight rows, 1-8, of the matrix. The current drivers of the current driver matrix 206 are respectively coupled to the set input windings of the magnetic cores occupying the last 15 rows of the matrix, rows 9-23. Therefore, the magnetic cores being magnetized correspond to the letter or figure decoded by the decode networks 196 and 198, respectively.

The selective magnetization of the cores of the matrix 208 to form a letter or figure is pictorially shown in FIG. 4. When a letter, such as the letter G is decoded, the magnetic cores are energized in a pattern corresponding to the letter. As shown in FIG. 4, when the letter G is decoded, the following cores are magnetized: A2, A3, A4, A5 and A6; B1 and B7; C1 and C7; D1, D5 and D7; E2, E5 and E6. When a figure, such as the figure 4 is decoded, the magnetic cores are magnetized in a pattern corresponding to the figure. As shown, when the figure 4 is decoded, the following cores are magnetized: A15, B14 and B15; C13 and C15; D12, D13, D14, D15, D16, D17 and D18; and E15. When a fraction, such as the fraction three-eighths is decoded, the cores are magnetized in the pattern corresponding to the fraction as shown in FIG. 4.

The output windings of the cores in each row of the matrix 208 are tied together and to the input terminals of 23 and" gates 210a-210n composing an electrical commutator 210. The read out windings of the cores in each column are also coupled together and tied through respective conductors 212, 213,214, 215 and 216 to the output terminals of the character position control circuits 190 and 193 associated with the upper New York Stock Exchange channel and the lower American Stock Exchange channel, respectively. The character position control circuits 190 and 193 control the sequential read out of the information stored in the columns of the core matrix 208. Specifically, when a signal is supplied through the conductor 212, the signal demagnetizes the cores in column E containing information such that signals from these demagnetized cores are supplied to the input terminals of the and gates 210a-210n. Similarly, when gating pulses are supplied through conductors 213, 214, 215 and 216, the cores in columns D, C, B, and A, respectively, containing information will be demagnetized and corresponding voltage signals will be supplied to the gates 210a-210n. The gates 210a-210n having bits of information supplied thereto are sequentially enabled by the timing pulses T0-T22, as will be more fully described hereinafter, and accordingly, sequentially transmit the stored information.

To more fully understand the transfer of information from the core matrix 208 to the electrical commutator 210, reference may be had to FIGS. 1A and 2B. As above-mentioned, the character present flip-flop 68 in the character advance control circuit is set when a character available signal is supplied from the six-bit buffer 34. The setting of the flip-flop 68 implements the enabling of either the gate 70 or the gate 72, the gate 70 being enabled when a 7.5 level signal is present and the gate 72 being enabled when a 15 level signal is present. Also, as above described, when the and gate 70 is enabled, a pulse is transmitted by the gate to the flip-flop circuit 78 to set the flip-flop. The flip-flop 78, in turn, provides a shift pulse to the input terminal 80a of the binary counter 80 to reset the counter. When the and gate 72 is enabled, a pulse is transmitted directly to the input terminal 800 of the counter 80 to reset the counter.

Upon the resetting of the counter 80, the count a and gate 82 is enabled. Enabling of the gate 82 implements the loading of new information bits 0-5 from the buffer 34 into the flipflops 148-153 in the 32 character recirculating buffer 38 (FIG. 2A) and the enabling of the and gate 92 in the off set counter programmer 94 (FIG. 2B). As above described, the and gate 92 is enabled with the simultaneous application of the count 0 signal, the CPFF signal and the reset level signal which is generated at a count of 262 lines and which has a pulse width of 32 microseconds (TO-T63). The output terminal of the and" gate 92 is coupled through a pair ofdiodes 218 and 220 and corresponding conductors 221 and 222, respectively, to the set input terminals of the last two stages in a three stage binary counter 224. In the lower channel, the offset counter programmer is similarly connected to a three stage binary counter 226. Accordingly, when the and" gate 92 is enabled, which is for the duration of the reset level signal, the last two stages of the counter 224 are set into the 1 states such that the counter has a count of 6. The binary counters 224 and 226 are reset to counts of 0 respectively at the end of a count of 262 lines by the leading edge of the reset level signal.

The output terminals of the three stages composing the counter 224 are coupled via six conductors 228 to the character position control circuit 190 and to the shift signal generator 166. The three stage binary counter 226 in the lower channel is similarly connected via six conductors 230 to the character position control circuit 194 and to the shift signal generator 176. The character position control circuit 190 comprises the and" gates 180, 182, 184, 186 and 188 which decode the count in the binary counter 224 into five line pulses Line 0, Line 1, Line 2, Line 3 and Line 4. Accordingly, when the counter 224 counts from 0-4 and a H signal is present (TO-T63) the gates 180, 182, 184, 186 and 188 are correspondingly enabled and when the counter 224 accumulates a count greater than 4, i.e., 5-7, the gates are disabled. The gates 180, 182, 184, 186 and 188 supply the pulses to the columns E, D, C, B and A respectively of the core matrix 208 through the conductors 212, 213, 214, 215 and 216, respectively, to sequentially read out information from the cores. The output terminals of the gates are also connected to corresponding gates in the character position control circuit 193 in the lower channel through the conductors 212,213,214, 215 and 216, respectively. These gates are enabled when a 14 signal is present (T64-T127). As above described, when the last stage u of the 128 binary counter 44 (FIG. 1B) is in the 0 state (TO-T63), a H signal from this stage tends to enable the gates 180, 182, 184, 186 and 188. During the count from T64-T127, a u signal is provided and this tends to enable the gates of the character position control circuit 193 in the lower channel.

The shift signal generator 166 is a three input and gate which is enabled when a count of 6 is reached by the counter 224. When enabled, the gate 166 supplies the line 6 signal through the conductor 167 to the input terminal 164a of the and gate 164 within the recirculating buffer control circuit 98 (FIG. 2A). As above-mentioned, the other input terminal 1641) of the gate 164 is coupled to the timing decode network 56 (FIG. 1B) which develops a h microsecond pulse T when a count of 120 is reached in the counter 44. As shown in FIG. 2A, with the simultaneous application of the T120 pulse and the line 6 signal to its input terminals 164a and 164b, the gate 164 transmits the T120 pulse to the amplifier 116 which generates a shift pulse. This shift pulse is supplied directly to the shift input terminals of the registers 136-141 and through the and gate 118 to the shift input terminals of the flip-flops 148-153 to implement the advancement and read out of the stored character bits.

As above-mentioned, with the resetting of the two stage binary counter 80 in the character advance control circuit 30, new bits of information are shifted into the flip-flops 148-153 of .the recirculating buffer 38. From T0-T63 or 32 microseconds because of the presence of the H signal, these bits are transmitted by the and gates 154-159 of the gate to the character matrix generator 194 and stored therein. From T64-T127 because of the presence of the 6 signal, the

new bits loaded in the 32 character recirculating buffer 40 of the lower channel are transmitted by the gates 169-174 of the gate 168 to the character matrix generator 194 and stored therein. This alternate transmittal of the same bits from the buffers 38 and 40 by the gates 160 and 168, respectively, takes place for eight line time periods or until a line 6 signal is generated by the shift signal generators 166 and 176.

Accordingly, when new bits are loaded into the flip-flops 148-153 of the buffer 38 and read out, these bits remain applied to the input terminals of the gates 154-159 until a line 6 pulse is generated. However, the line 6 pulse is generated immediately because of the loading of a count of 6 into the three stage binary counter 224. Accordingly, approximately 60 microseconds after new bits are loaded into the flip-flops 148-153, the bits stored in the first stages of the registers 136-141 are shifted into the flip-flops 148-153 and read out. It will be noted that during this time, that is, from T to T120, the bits from the upper and lower 32 character recirculating buffers 38 and 40 will have been alternately stored in patterns corresponding to the letter or figure corresponding to the new bits in the core matrix 208 of the character matrix generator. The cores will not have been demagnetized, however, since during this time, the line scanning gates 180, 182, 184, 186 and 188 of the character position control circuit 190 and the gates of the lower channel control circuit 193 will not have been enabled.

The three stage binary counters 224 and 226 are stepped by a T128 pulse supplied from the timing signal decode network 56 through a conductor 235. Because the counters 224 and 226 had initially loaded therein the number six, the first T128 pulse steps each of the counters 224 and 226 to the number seven. The following T128 pulse steps each of the counters to 0. With a count of(), the and gate 180 in the character position control circuit 190 is enabled for 32 microseconds (TO-T63) because of the presence of the '11 signal and the magnetized cores in column E of the core matrix 208 are demagnetized. During the next 32 microseconds (T64-T127), the cores of the matrix 208 are magnetized in an array corresponding to the character transferred from the lower channel 32 character recirculating buffer 40 and column E will be enabled by a corresponding line 0 signal generated by the character position control circuit 193.

As above-mentioned with reference to FIGS. 18 and 2C, the 23 gates 210a-210n of the commutator 210 are enabled by timing pulses T0-T22 to implement the sequential read out of the stored character patterns. Specifically, the timing signal decode network 56 decodes, inter alia, the first five stages of the counter 44 into 23 timing pulses, T0-T22. These pulses are supplied from the network 56 through a cable 237 to the other input terminals of the gates 210a-210n in the commutator to thereby sequentially enable the gates. Because the signals from column E of the core matrix 208 which correspond to the last line of the character transmitted from the recirculating buffer 38 are present at the input terminals of the gates 210a-210n for a period of 32 microseconds, T0-T63, these bits are sequentially transmitted by the gates 2l0a-2l0n a total number of two times. During the next 32 microseconds T64-T127, column E of the core matrix 208 corresponding to the last line of the character transmitted from the buffer 40 is enabled and these signals are sequentially transmitted a total number of two times by the gates 210a- 210n.

The three stage binary counter 224 is then stepped to counts of 1, 2, 3 and 4 in the above-described manner by the application of the T128 pulse and the gates 182, 184, 186 and 188 are sequentially enabled to implement the gating of core columns D, C, B and A, respectively, at T0-T63 and the signals read out from these core columns are sequentially transmitted by the gates 210a210n a total of two times. Similarly, the lower channel three stage binary counter 226 is stepped by the T128 pulse every 64 microseconds, the gates of the character position control circuit 193 are sequentially enabled at T64-T127 and the core columns D, C, B and A are gated and the signals read out from these columns are sequentially transmitted by the gates 210a-210n a total oftwo times.

When the binary counters 224 and 226 accumulate counts of 5, 6 and 7, no transfer of information takes place. Hence, there is an inactive period of three lines. However, when the counters 224 and 226 reach counts of 6, at T120, the contents of the recirculating buffers 38 and 40 are advanced such that new characters from the buffers 38 and 40 are alternately stored in the core matrix 208 of the character matrix generator. The columns of the core matrix 208 are not gated until the counters 224 and 226 are reset to 0" counts, respectively, as above-described.

The above sequence of operation continues until the 32 characters stored in the recirculating buffers 38 and 40 are transmitted and the patterns formed in the core matrix corresponding to the characters are sequentially transmitted a total number of two times. It will be noted that the character which was initially loaded into the flip-flops 148-153 of the buffer 38 and the flip-flops of the buffer 40 will not have been read out. As above-described, a count 6 is initially loaded into both the counters 224 and 226 such that the core magnetization patterns of the core matrix 208 corresponding to the characters are never enabled.

After a count of 262, the reset level signal is generated. This reset level signal resets the three stage binary counters 224 and 226 and enables either the and" gate 70 or the and" gate 72 in the character advance control circuit 30 depending upon whether a 7.5 level signal or a 15 level signal is present. If the and gate 70 is enabled, the gate 70 transmits a pulse which resets the flip-flop 78. Resetting of the flip-flop 78 has no effect on the two stage binary counter 80 such that the counter 80 remains reset. However, resetting of the flip-flop 78 disables the and gate 96 in the recirculating buffer control circuit 98 such that the and gate 118 and the and" gates 124-129 remain enabled. Only when the flip-flop 78 is set will the two stage counter 80 be advanced. Accordingly, the count 0 and" gate 82 will remain enabled and a 6 will be loaded into the three stage binary counter 224 through the diodes 218 and 220. Because newest character bits are stored in the first stage of the registers 136 and 141 and will be present at the input terminals of the flip-flops 148-153, of the recirculating buffer 38 (FIG. 1A, 2A), the same character bits are shifted into the flip-flops 148-153 in the manner described above. This is described in more detail relative to the description of the 15 level operation. It will be noted that because the character present flip-flop remains in the 1" state, no transfer of bits will occur between the gate 18 and the six-bit buffer 34 (FIG. 1A).

If, however, a 15 level signal is present, the and gate 72 will be enabled and the two stage binary counter 80 will be stepped when the reset level signal enables the gate 72. Stepping the binary counter 80 to a count of 1 enables the count 1 and" gate 84. 1t will be noted that because the count 0 and gate 82 is disabled, the and gate 96 in the recirculating buffer control circuit 98 is disabled. This precludes the transfer of new character bits into the buffer 38. Application of the reset level signal enables the and" gate 112 such that a shift pulse is supplied to both the flip-flops 148-153 and the registers 136-141 and the bits stored in the first stages of the registers 136-141 are transferred into the flip-flops 148-153 respectively. It will be noted that the bits stored in the first stages of registers 136-141 are the bits which had been shifted into the flip-flops 148-153 from the and gates 124-129, respectively at the start of the operation, that is, when the character present flip-flop 68 was initially set. This is true because there are 32 shift pulses (line 6, T) every 262% lines and after 32 shift pulses, the characters initially loaded into the flip-flops 148-153 will have been shifted down to the first stages of the registers 136-141.

Setting of the count 1 and gate implements the enabling of the and" gate 104 in the offset counter programmer 94. The and gate 104 is coupled through a diode 240 to the conductor 22] which leads to the last stage of the three stage binary counter 224. When the gate 104 is enabled by the reset level signal, the CPFF signal and the count 1 signal, the gate supplies a pulse through the diode 240 to the set input termm (Nil.

minal of the last stage flip-flop in the counter 224 to set the flip-flop into the 1 state. The counter 224 therefore has a count of 4. Setting a count of 4 into the counter 224 implements the enabling of the line 4 and" gate for the time period T-T63 (i) and column A of the core matrix 208 is enabled. Thereafter, upon the application of the T128 pulse to its input terminal, the three stage binary counter 224 the counter accumulates counts of 5, 6 and 7 during which there is no transfer of information from the core matrix 208 to the electrical commutator. However, when the counter 224 reaches a count of 6, the shift signal generator 166 generates a line 6 signal which, together with a T120 signal, implements the further shifting of the contents in the recirculating buffer 38. It will be noted that there is a delay of four lines or 256 microseconds (4 X 64) between the start of the operational cycle and the time when an entire pattern of cores corresponding to a character is read out from the core matrix 208.

During the third operational cycle when a level signal is present, the two stage binary counter 80 in the character advance control circuit 30 will be stepped to a count of 2 with the application of the reset level signal after 262 lines. Stepping of the counter 80 to a count of 2 enables the count 2 and gate 86 which, in turn, and together with the reset level signal enables the and gate 106 in the offset counter programmer 94. The output terminal of the gate 106 is coupled through a diode 241 to the conductor 222 and conducted thereby to the set input terminal of the second stage in the binary counter 224. This sets the second stage flip-flop into the 1" state such that a count of 2 is loaded into the counter. Accordingly, the line 2 and" gate 184 in the character position control circuit 190 will be enabled and will enable column C of the core matrix 208. Again, the matrix 208 will have stored therein a coded pattern corresponding to the character shifted from the first stages of the registers 136-141 into the flip-flops 148-153, respectively, upon the application of the reset level signal. This character was initially loaded into the flip-flops 148-153 via the gates 130-135, respectively, during the first operational cycle, as above-described.

As the binary counter 224 is stepped every 64 microseconds by the T128 pulse to counts of 3, 4, 5, 6 and 7, it can be seen that three-fifths of the coded pattern of magnetized cores, that is, columns C, B and A of the core matrix 208, corresponding to the decoded character will be enabled and read out. During the third operational cycle, there is a lag of six lines between the start of the cycle and the time when an entire pattern of cores corresponding to a character is read out from the core matrix.

During the fourth 15 level operational cycle, the counter 80 is stepped to a count of 3 to implement the enabling of the count 3 and gate 88-. When enabled, the gate 88 supplies a pulse to the reset input terminal 680 of the character present flip-flop 68 to reset the flip-flop. This signifies that the 32 character recirculating buffer 38 is able to accept an additional character, as above-described. As above-mentioned, the reset level signal resets the binary counters 224 and 226 at the end of every operational cycle. Accordingly, when the counter 80 in the character advance control circuit 30 steps to a count of 3, the three stage binary counter 224 has a zero count therein. Moreover, the stages of the counter are not externally triggered into the l states as during the first, second and third cycles such that the counter retains a 0 count. With the binary counter 222 having a 0 count, the line 0 and gate in the character position control circuit 190 will be enabled from T0-T63 (u) and generate a line 0 signal. This signal enables the column E of the core matrix 208. Thereafter as the counter is stepped from a count of 0 to a count of 4, the remaining core columns D, C, B and A are enabled such that the entire coded array corresponding to the character initially loaded into the recirculating buffer 38 is read out.

With a 7.5 level signal present, the read out of the entire character occurs in the seventh operational cycle. Specifically, beginning with the two stage binary counter 80 being initially reset to O, the first two operational cycles begin with a count of 6 being loaded into the binary counter 224 such that a full character is read out after a delay of two lines. During the next two cycles, the binary counter 224 has a count of 4 loaded therein such that one core column E of the newest character is read out and there is a full character read out of a previously stored character after a delay of four lines. In the fifth and sixth cycles, the binary counter 224 has a count of 2 loaded therein such that three core columns, E, D and C, of the newest character are read out and there is a full character read out of a previously stored character after a delay of six lines. Finally, in the seventh and following cycles, no count is loaded into the counter 224 such that all five core columns E, D, C, B and A of the newest character are read out and there is a delay of eight lines before the next previously stored character is read out. It may be noted that following the seventh cycle, new character bits will be accepted by the 32 character recirculating buffer 38 such that the above described operational sequence will occur. This is true because the character present flip-flop 68 in the character advance control circuit 30 is reset when a count of 3 is accumulated by the two stage binary counter 80.

As above described with reference to FIGS. 2B and 2C, when the line 0 and" gate in the character position control circuit of the upper channel is enabled, column E of the core matrix 208 is enabled by the line 0 signal and the core output signals are supplied to the gates 210a-210n of the electrical commutator 210. The timing pulses T0-T23 enable the gates 2l0a-210n a total number of two times in the first 32 microseconds to implement the double transmission of the column E core signals. During the next 32 microseconds (T64-Tl27) with the u flip-flop of the counter 44 in the 1" state, the line 0 and gate in the character position control circuit 193 is enabled and column E of the core matrix 208 is enabled by the line 0 signal. Again, the core output signals are sequentially transmitted twice by the gates 2l0a-2l0n. The above operation repeats itself as the counters 224 and 226 are stepped from counts of 0 through counts of 4 and the core columns D, C, B and A are enabled by the lines 1, 2, 3 and 4 signals, respectively.

As shown in FIG. 18, from the gates 2l0a-210n, the enabled core signals are supplied to the input terminal of a masking circuit 244. The masking circuit 244, which may comprise conventional gating circuitry, is also coupled via the conductors 179 and 192 to the opposite output terminals of the last stage flip-flop u in the 128 bit counter 44 and via conductors 245 and 246 to the output terminals of the next-to-last stage flip-flop v in the counter 44. The masking circuit 244 passes the sequentially transmitted core signals when the v flip-flop is set to the l state and the u flip-flop is reset to the 0 state (T32-T63 or vi) and passes the core signals when the v flipflop is set to the 0 state and the u flip-flop is set to the 1 state, (T96-T127 or $14). Obviously, the durations of the core output signals must last long enough to enable the gates and therefore, the core output signals, to be sampled sequentially by T0 to T22 pulses. Accordingly, from T0-T31, no signals are transmitted and from T64-T95 no core signals are transmitted.

The masked core signals are then sequentially supplied to a pulse shaping network 248, which may, for example, comprise an and" gate and which is also supplied with k microsecond pulses from the 2 ml-l/s clock 42 through a conductor 249. in the network 248, the k microsecond pulses are transmitted whenever a core output signal is present at the other input terminal of the network 248. Hence, in this manner the core signals are shaped into )5 microsecond pulses.

Thereupon, the A microsecond pulses are supplied to the video driver circuit 60 wherein the signals are combined with the vertical and horizontal sync pulses generated by the generator 58. From the video driver 60, the combined signals are coupled to an image reproducing device 250, which may be, for example, a cathode ray tube, for reproduction. As above mentioned, the horizontal and vertical sync pulses are also supplied to the scanning wave generator 62 which develops line deflecting and field deflecting sawtooth waves. From the scanning wave generator 62 the line deflecting and field deflecting sawtooth waves are supplied to the horizontal deflection coils and vertical deflection coils, respectively, of the scanning yoke 252 of the image reproducing device 250. The deflection coils of the yoke 252 are rotated 90 such that the horizontal deflection coils produce a vertical scan and the vertical deflection coils produce a horizontal scan. Specifically, the horizontal scan caused by the vertical deflection coils occurs from right to left across the face of the image reproducing device 250 and takes place in approximately onesixtieth ofa second. The vertical scan caused by the horizontal deflection coils occurs from top to bottom of the image reproducing device 250 and consumes 64 microseconds. Accordingly, the information is displayed as precessing from right to left across the face of the image reproducing device 250.

FlG. illustrates a typical picture provided by the image reproducing device 250. It will be noticed that the first and third quarters of the screen are blank. This is because of the above described masking action performed by the masking circuit 244. Each reproduced character occupies five vertical lines with three lines spacing adjacent characters. The effect of smooth motion by the reproduced characters is controlled by the offset counter programmers 94 and 100 and by their associated three stage binary counters 224 and 226, respectively. As above described, when new character bits are loaded into the recirculating buffers 38 and 40, there is an incremental displacement of two lines in the display of the characters between consecutive field scansions when a 15 level signal is present. Accordingly, the character progression speed is 15 characters per second. When a 7.5 level signal is present, the incremental displacement of two lines occurs during successive frame scansions and the character progression speed is therefore 7.5 characters per second. In this manner, either the upper display or the lower display will appear to move across the face of the image reproducing device at twice the speed of the other display if a 15 level signal is present in that channel and a 7.5 level signal is present in the other channel.

Although the invention has been described herein with reference to a specific embodiment many modifications and variations therein will readily occur to those skilled in the art. Accordingly, all such variations and modifications are included within the intended scope of the invention as defined by the following claims.

We claim:

1. Apparatus for providing a visual display of first and second received sequences of characters represented by first and second received sequences of character signals comprismg:

timing generator means for generating a pre-determined number oftiming signals;

first and second input register means for storing and reading out the first and second received sequences of character signals, respectively;

first and second transfer control means for sensing the number of received character signals present in said first and second input register means, respectively, and for generating first and second transfer control signals respectively indicative of the numbers of character signals present;

first recirculating buffer means for storing a selected number ofcharacter signals read out of said first input register means and responsive to certain of the timing signals generated by said timing generator means and to said first transfer control signals for simultaneously reading out and restoring the character signals stored therein; second recirculating buffer means for storing a selected number of character signals read out of said second input register means and responsive to certain of the timing signals generated by said timing generator means and to said second transfer control signals for simultaneously reading out and restoring the character signals stored therein; gate means responsive to the readout of character signals from said recirculating buffer registers and to selected timing signals generated by said timing generator means for alternately transmitting to the character generator means the character signals read out from said first and second recirculating buffer registers; character generator means responsive to the character signals read out from said first and second recirculating buffer means for converting the character signals to an electrical array, the array forming the character represented by the character signals being read out;

scanning means responsive to certain other timing signals generated by said timing generator means for scanning the array corresponding to the character being read out;

image reproducing means responsive to the output of said scanning means for displaying the first and second sequences of characters in rows on a display screen, said image reproducing means including deflection means responsive to still other timing signals generated by said timing generator means for implementing line scanning in the first direction and field scanning in a second direction, the characters being sequentially presented on a display screen in rows which are oriented in the direction of field scanning;

first offset counter means responsive to said first transfer control signals for controlling the initial scan of said array to thereby produce an incremental positioning in the reproduction of the first sequence of characters by said image reproducing means in accordance with the number of character signals present in said first input register means; and

second offset counter means responsive to said second transfer control signals for controlling the initial scan of said array to thereby produce an incremental positioning in the reproduction of the second sequence of characters by said image reproducing means in accordance with the number of character signals present in said second input register means.

2. Apparatus in accordance with claim 1 wherein the incremental positionings in the reproduction of the first and second characters is achieved by offsetting the displayed characters by a number of scan lines, the offset being synchronized with the rate of field scanning.

3. Apparatus in accordance with claim 2 wherein the offset of the displayed characters is synchronized at the rate of two lines per field scansion for particular transfer control signals and at a rate of four lines per field scansion for different transfer control signals.

4. Apparatus in accordance with claim 1 further comprising coordinating circuit means responsive to said selected timing signals for receiving character signals from said scanning means and for transmitting selected character representative signals to said image reproducing means such that characters represented by the transmitted signals are displayed on different portions of the image reproducing device.

5. Apparatus in accordance with claim 2 wherein said first direction is the vertical direction and said second direction is the horizontal direction.

tun. t. 

1. Apparatus for providing a visual display of first and second received sequences of characters represented by first and second received sequences of character signals comprising: timing generator means for generating a pre-determined number of timing signals; first and second input register means for storing and reading out the first and second received sequences of character signals, respectively; first and second transfer control means for sensing the number of received character signals present in said first and second input register means, respectively, and for generating first and second transfer control signals respectively indicative of the numbers of character signals present; first recirculating buffer means for storing a selected number of character signals read out of said first input register means and responsive to certain of the timing signals generated by said timing generator means and to said first transfer control signals for simultaneously reading out and restoring the character signals stored therein; second recirculating buffer means for storing a selected number of character signals read out of said second input register means and responsive to certain of the timing signals generated by said timing generator means and to said second transfer control signals for simultaneously reading out and restoring the character signals stored therein; gate means responsive to the readout of character signals from said recirculating buffer registers and to selected timing signals generated by said timing generator means for alternately transmitting to the character generator means the character signals read out from said first and second recirculating buffer registers; character generator means responsive to the character signals read out from said first and second recirculating buffer means for converting the character signals to an electrical array, the array forming the character represented by the character signals being read out; scanning means responsive to certain other timing signals generated by said timing generator means for scanning the array corresponding to the character being read out; image reproducing means responsive to the output of said scanning means for displaying the first and second sequences of characters in rows on a display screen, said image reproducing means including deflection means responsive to still other timing signals generated by said timing generator means for implementing line scanning in the first direction and field scanning in a second direction, the characters being sequentially presented on a display screen in rows which are oriented in the direction of field scanning; first offset counter means responsive to said first transfer control signals for controlling the initial scan of said array to thereby produce an incremental positioning in the reproduction of the first sequence of characters by said image reproducing means in accordance with the number of character signals present in said first input register means; and second offset counter means responsive to said second transfer control signals for controlling the initial scan of said array to thereby produce an incremental positioning in the reproduction of the second sequence of characters by said image reproducing means in accordance wIth the number of character signals present in said second input register means.
 2. Apparatus in accordance with claim 1 wherein the incremental positionings in the reproduction of the first and second characters is achieved by offsetting the displayed characters by a number of scan lines, the offset being synchronized with the rate of field scanning.
 3. Apparatus in accordance with claim 2 wherein the offset of the displayed characters is synchronized at the rate of two lines per field scansion for particular transfer control signals and at a rate of four lines per field scansion for different transfer control signals.
 4. Apparatus in accordance with claim 1 further comprising coordinating circuit means responsive to said selected timing signals for receiving character signals from said scanning means and for transmitting selected character representative signals to said image reproducing means such that characters represented by the transmitted signals are displayed on different portions of the image reproducing device.
 5. Apparatus in accordance with claim 2 wherein said first direction is the vertical direction and said second direction is the horizontal direction. 